This topic describes the differences in features and limits between enhanced Internet NAT gateways and standard Internet NAT gateways.
Differences in features
| Item | Enhanced Internet NAT gateway | Standard Internet NAT gateway | References |
|---|---|---|---|
| Deploying multiple Internet NAT gateways in the same virtual private cloud (VPC) | Supported | Not supported | Deploy multiple NAT gateways in one VPC |
| Associating a vSwitch with an Internet NAT gateway | Supported | Not supported | N/A |
| Billed on an hourly basis | Supported | Not supported | Pay-by-actual-usage |
| Processing TCP, UDP, and ICMP fragments | Supported | Not supported | N/A |
| Metrics | 22 | 4 | Monitor and maintain Internet NAT gateways |
| Associating multiple elastic IP addresses (EIPs) with an Internet NAT gateway | Supported | Supported | Associate an EIP with a NAT gateway |
| SNAT | Supported | Supported | Create an SNAT entry on an Internet NAT gateway |
| Creating multiple SNAT entries in an SNAT table | Supported | Supported | |
| Associating multiple EIPs with an SNAT table | Supported | Supported | |
| DNAT | Supported | Supported | Create a DNAT entry on an Internet NAT gateway |
| DNAT port mapping | Supported | Supported | |
| DNAT IP mapping | Supported | Supported | |
| Elastic Compute Service (ECS) instances use SNAT to access DNAT services that belong to the same Internet NAT gateway | Not supported | Supported | N/A |
| Using an EIP for both SNAT and DNAT tables | Supported | Not supported |
Comparison of limits
| Limit | Enhanced Internet NAT gateway | Standard Internet NAT gateway |
|---|---|---|
| The maximum number of Internet NAT gateways that can be created in a VPC | 5. To increase the quota, submit a ticket. | 1. You cannot adjust the quota. |
| The maximum number of DNAT entries that can be added to an Internet NAT gateway | 100. You can increase the quota. For more information, see Manage quotas. | 100. You can increase the quota. For more information, see Manage quotas. |
| The maximum number of SNAT entries that can be added to an Internet NAT gateway | 40. You can increase the quota. For more information, see Manage quotas. | 40. You can increase the quota. For more information, see Manage quotas. |
| The maximum number of public IP addresses that you can specify in an SNAT entry | 64. You cannot adjust the quota. | 64. You cannot adjust the quota. |
| Creating an Internet NAT gateway for a VPC that contains a custom route whose destination CIDR block is 0.0.0.0/0 | Supported | Not supported. You must delete the custom route entry whose destination CIDR block is 0.0.0.0/0 before you can create an Internet NAT gateway for the VPC. |
| Whether a vSwitch is limited by the bandwidth limit of an EIP after the vSwitch is associated with an SNAT entry | Yes. If the EIP is associated with an EIP bandwidth plan, the vSwitch is limited by the bandwidth limit of the EIP bandwidth plan. | Yes. If the EIP is associated with an EIP bandwidth plan, the vSwitch is limited by the bandwidth limit of the EIP bandwidth plan. |
| The maximum number of EIPs that can be associated with an Internet NAT gateway | 20. You can increase the quota. For more information, see Manage quotas. | 20. You can increase the quota. For more information, see Manage quotas. |
| The bandwidth limit of an Internet NAT gateway | 5 Gbit/s. If the total bandwidth of the EIPs or EIP bandwidth plans is greater than 5 Gbit/s,submit a ticket to increase the quota. | An Internet NAT gateway does not have a bandwidth limit itself. However, the bandwidth
of an Internet NAT gateway is limited by the bandwidth limits of the EIPs that are
associated with SNAT or DNAT entries. The bandwidth is also limited by the bandwidth
limits of the EIP bandwidth plans with which the EIPs are associated.
For example, you create an SNAT entry for an Internet NAT gateway, and specify five pay-by-data-transfer EIPs and two pay-by-bandwidth EIPs whose bandwidth limits are 500 Mbit/s. The bandwidth of the Internet NAT gateway is limited to 2,000 Mbit/s. This value is calculated based on the following formula: 5 × 200 Mbit/s + 2 × 500 Mbit/s = 2,000 Mbit/s. If the seven EIPs are associated with the same EIP bandwidth plan, and the bandwidth limit of the EIP bandwidth plan is 1,000 Mbit/s, the bandwidth limit of the Internet NAT gateway is 1,000 Mbit/s. |
| The maximum number of concurrent connections for an EIP is 55,000. | Yes | Yes |
| The bandwidth limit of an EIP in an EIP bandwidth plan is 200 Mbit/s. | No | Yes |
| Users of NAT service plans cannot associate EIPs with NAT gateways. | Yes | Yes |
| You can change the bandwidth limit of an EIP bandwidth plan that is associated with an Internet NAT gateway. For example, you can increase the bandwidth limit from less than 1 Gbit/s to greater than 1 Gbit/s. You can also decrease the bandwidth limit from greater than 1 Gbit/s to less than 1 Gbit/s. When you change the bandwidth limit of an EIP bandwidth plan, temporary service interruptions may occur. | No | Yes |
| Temporary service interruptions may occur when IP addresses in existing SNAT entries are reduced. | Yes | Yes |
| Temporary service interruptions may occur when IP addresses in the existing SNAT entries are increased. | No | Yes |
| Whether the ECS instance can be accessed from the Internet in the following scenario: Multiple elastic network interfaces (ENIs) are attached to an ECS instance, and an EIP is associated with one of the ENIs. Different ENIs are used to forward the inbound and outbound traffic of the ECS instance. | No. You must modify the route of the ECS instance before you upgrade the standard Internet NAT gateway to an enhanced Internet NAT gateway. Make sure that the inbound and outbound traffic of the ECS instance is forwarded by the same ENI. For more information, see Configure routes for ENIs. | Yes |